This invention relates to a novel process for the oxidation of olefins and secondary and tertiary alkylaromatic hydrocarbons to form various oxidation products, particularly hydroperoxides, or the decomposition products thereof, i.e. alcohols, aldehydes, ketones, and the like, or mixtures thereof. More particularly, this invention is directed to the use of complexes formed by reacting metal salts with a trialkylphosphate (TAP) as oxidation catalysts in the aforesaid process, and especially those complexes formed between TAP and lanthanide metal salts. The term "lanthanide metal salts" is intended to include the metal lanthanum as well as other metals in this series.
The oxidation of olefins and the alkyl side chains of aromatic compounds is already well known in the art. Thus, for example, it is known that tertiary alkylaromatics such as cumene can be auto-oxidized very slowly to form cumyl hydroperoxide when air or oxygen is rapidly passed through cumene warmed to about 80.degree. C. Also, Canadian Patent No. 510,517 teaches that the rate of oxidation of cumene can be enhanced when carried out in the presence of alkali or alkaline earth metal oxides or hydroxides, or in the presence of salts and oxides of heavy metals. Under these conditions, the conversion rate is only 2 to 3 percent per hour. Other oxidation catalysts are likewise well known, but in most instances, again, the conversion rate is low, as is the overall yield of the desired oxidation product.
It is an object of this invention, therefore, to provide a novel process for the oxidation of olefins and secondary and tertiary alkylaromatic compounds whereby, in particular, the oxidation rate, or the selectivity, for hydroperoxide formation, or both, may be increased.